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Power calculation

Daniel S Quintana
The calculation of heart rate variability (HRV) is a popular tool used to investigate differences in cardiac autonomic control between population samples. When interpreting effect sizes to quantify the magnitude of group differences, researchers typically use Cohen's guidelines of small (0.2), medium (0.5), and large (0.8) effects. However, these guidelines were originally proposed as a fallback for when the effect size distribution (ESD) was unknown. Despite the availability of effect sizes from hundreds of HRV studies, researchers still largely rely on Cohen's guidelines to interpret effect sizes and to perform power analyses to calculate required sample sizes for future research...
December 3, 2016: Psychophysiology
Christopher D Chouinard, Vinícius Wilian D Cruzeiro, Adrian E Roitberg, Richard A Yost
Ion mobility-mass spectrometry (IM-MS) has recently seen increased use in the analysis of small molecules, especially in the field of metabolomics, for increased breadth of information and improved separation of isomers. In this study, steroid epimers androsterone and trans-androsterone were analyzed with IM-MS to investigate differences in their relative mobilities. Although sodiated monomers exhibited very similar collision cross-sections (CCS), baseline separation was observed for the sodiated dimer species (RS = 1...
December 2, 2016: Journal of the American Society for Mass Spectrometry
Xia Jiang, Johan Askling, Saedis Saevarsdottir, Leonid Padyukov, Lars Alfredsson, Sebastien Viatte, Thomas Frisell
BACKGROUND: To prevent debilitating and irreversible joint damage, rheumatoid arthritis (RA) is often treated with tumor necrosis factor inhibitor (TNFi), but many patients do not respond to this costly therapy. Few predictors for response are known, and it has been proposed that genetic factors which influence the development of RA may also influence disease severity and response to therapy. Several previous studies have attempted to confirm this but results remain inconclusive. We expand on previous studies by including more RA risk alleles, and maximize power by combining them into a genetic risk score...
December 3, 2016: Arthritis Research & Therapy
M E Griswold, S Korepanov, M C Thompson
An end loss analyzer system consisting of electrostatic, gridded retarding-potential analyzers and pyroelectric crystal bolometers was developed to characterize the plasma loss along open field lines to the divertors of C-2U. The system measures the current and energy distribution of escaping ions as well as the total power flux to enable calculation of the energy lost per escaping electron/ion pair. Special care was taken in the construction of the analyzer elements so that they can be directly mounted to the divertor electrode...
November 2016: Review of Scientific Instruments
Seung Hun Lee, J H Lee, I Yamada, Jae Sun Park
Neural networks provide powerful approaches of dealing with nonlinear data and have been successfully applied to fusion plasma diagnostics and control systems. Controlling tokamak plasmas in real time is essential to measure the plasma parameters in situ. However, the χ(2) method traditionally used in Thomson scattering diagnostics hampers real-time measurement due to the complexity of the calculations involved. In this study, we applied a neural network approach to Thomson scattering diagnostics in order to calculate the electron temperature, comparing the results to those obtained with the χ(2) method...
November 2016: Review of Scientific Instruments
June-Woo Juhn, K C Lee, H M Wi, Y S Kim, Y U Nam
The 2015 KSTAR experimental campaign was the first year of routine measurement with a far infrared interferometer (FIRI) utilizing 118.87 μm CH3OH lasers at maximum 200 mW CW beam power. By using rtEFIT reconstruction, the path lengths of interferometers can be calculated and so the line-averaged electron densities n¯e from the FIRI and a millimeter-wave interferometer were in excellent agreement. In this way, the number of successfully diagnosed discharges is counted: 1003 shots or 83.7% of sustained discharges, defined as shots of plasma current IP ≥ 0...
November 2016: Review of Scientific Instruments
G G van Eden, M L Reinke, B J Peterson, T K Gray, L F Delgado-Aparicio, M A Jaworski, J Lore, K Mukai, R Sano, S N Pandya, T W Morgan
The InfraRed Video Bolometer (IRVB) is a powerful tool to measure radiated power in magnetically confined plasmas due to its ability to obtain 2D images of plasma emission using a technique that is compatible with the fusion nuclear environment. A prototype IRVB has been developed and installed on NSTX-U to view the lower divertor. The IRVB is a pinhole camera which images radiation from the plasma onto a 2.5 μm thick, 9 × 7 cm(2) Pt foil and monitors the resulting spatio-temporal temperature evolution using an IR camera...
November 2016: Review of Scientific Instruments
P W Ross, R F Heeter, M F Ahmed, E Dodd, E J Huffman, D A Liedahl, J A King, Y P Opachich, M B Schneider, T S Perry
Recent experiments at the Sandia National Laboratory Z facility have called into question models used in calculating opacity, of importance for modeling stellar interiors. An effort is being made to reproduce these results at the National Ignition Facility (NIF). These experiments require a new X-ray opacity spectrometer (OpSpec) spanning 540 eV-2100 eV with a resolving power E/ΔE > 700. The design of the OpSpec is presented. Photometric calculations based on expected opacity data are also presented. First use on NIF is expected in September 2016...
November 2016: Review of Scientific Instruments
A M Rasmus, A U Hazi, M J-E Manuel, C C Kuranz, S R Klein, P X Belancourt, J R Fein, M J MacDonald, R P Drake, B B Pollock, J Park, G J Williams, H Chen
Ultra-intense short pulse lasers incident on solid targets (e.g., thin Au foils) produce well collimated, broad-spectrum proton beams. These proton beams can be used to characterize magnetic fields, electric fields, and density gradients in high energy-density systems. The LLNL-Imaging Proton Spectrometer (L-IPS) was designed and built [H. Chen et al., Rev. Sci. Instrum. 81, 10D314 (2010)] for use with such laser produced proton beams. The L-IPS has an energy range of 50 keV-40 MeV with a resolving power (E/dE) of about 275 at 1 MeV and 21 at 20 MeV, as well as a single spatial imaging axis...
November 2016: Review of Scientific Instruments
Felix Friedländer, Ferdinand Bohmann, Max Brunkhorst, Ju-Hee Chae, Kavi Devraj, Yvette Köhler, Peter Kraft, Hannah Kuhn, Alexandra Lucaciu, Sebastian Luger, Waltraud Pfeilschifter, Rebecca Sadler, Arthur Liesz, Karolina Scholtyschik, Leonie Stolz, Rajkumar Vutukuri, Robert Brunkhorst
Despite the efficacy of neuroprotective approaches in animal models of stroke, their translation has so far failed from bench to bedside. One reason is presumed to be a low quality of preclinical study design, leading to bias and a low a priori power. In this study, we propose that the key read-out of experimental stroke studies, the volume of the ischemic damage as commonly measured by free-handed planimetry of TTC-stained brain sections, is subject to an unrecognized low inter-rater and test-retest reliability with strong implications for statistical power and bias...
December 1, 2016: Journal of Cerebral Blood Flow and Metabolism
Aishani Ghosal, Binny J Cherayil
In an extension of earlier studies from this group on the application of the Jarzynski equality to the determination of the elastic properties of a finitely extensible Rouse model of polymers under flow [A. Ghosal and B. J. Cherayil, J. Chem. Phys. 144, 214902 (2016)], we derive several new theoretical results in this paper on the nature of the distribution function P(w) that governs the long-time limit t>1 of the fluctuations in the work w performed by the polymer during flow-induced stretching. In particular, we show that an expression for the average of the nth power of the work, ⟨w(n)(t)⟩, can be obtained in closed form in this limit, making it possible to exactly calculate three important statistical measures of P(w): the mean μ, the skewness γ1, and the kurtosis γ2 (apart from the variance σ(2))...
November 28, 2016: Journal of Chemical Physics
Fernanda O Laranjeira, Everton Nunes da Silva, Maurício G Pereira
BACKGROUND: Long-acting insulin analogues for type 1 diabetes (T1D) treatment have been available on the Brazilian market since 2002. However, the population cannot access the analogues through the public health system. OBJECTIVE: To estimate the incremental budget impact of long-acting insulin analogues coverage for T1D patients in the Brazilian public health system compared to NPH insulin. METHODS: We performed a budget impact analysis of a five-year period...
2016: PloS One
Christoph Alexander Bauer, Andreas Hansen, Stefan Grimme
The fractional occupation number weighted density (FOD) analysis is explored as a general theoretical diagnostic for complicated electronic structures. Its main feature is to provide robustly and fast the information where 'hot' (strongly correlated and chemically active) electrons are localized in a molecule. We demonstrate its usage in four different prototypical applications: (i) As a new and fast measure for the biradical character of polycyclic aromatic hydrocarbons, (ii) for the selection of active orbital spaces in multiconfigurational or complete active space self consistent field (MCSCF/CASSCF) treatments, (iii) as a possibility to consistently describe molecular energy landscapes in regions with varying biradical character as exemplified by partial double bond torsions, and (iv) as a powerful visualization method for static electron correlation effects in large biomolecules in connection with an efficient semi-empirical tight-binding molecular orbital scheme...
December 1, 2016: Chemistry: a European Journal
V H Arístizabal, F J Vélez, E Rueda, N D Gómez, J A Gómez
Although experimental advances in the implementation and characterization of fiber speckle sensor have been reported, a suitable model to interpret the speckle-pattern variation under perturbation is desirable but very challenging to be developed due to the various factors influencing the speckle pattern. In this work, a new methodology based on the finite element method (FEM) for modeling and optimizing fiber specklegram sensors (FSSs) is proposed. The numerical method allows computational visualization and quantification, in near field, of changes of a step multi-mode fiber (SMMF) specklegram, due to the application of a uniformly distributed force line (UDFL)...
November 28, 2016: Optics Express
Alex Dornburg, J Nick Fisk, Jules Tamagnan, Jeffrey P Townsend
BACKGROUND: Analyses of phylogenetic informativeness represent an important step in screening potential or existing datasets for their proclivity toward convergent or parallel evolution of molecular sites. However, while new theory has been developed from which to predict the utility of sequence data, adoption of these advances have been stymied by a lack of software enabling application of advances in theory, especially for large next-generation sequence data sets. Moreover, there are no theoretical barriers to application of the phylogenetic informativeness or the calculation of quartet internode resolution probabilities in a Bayesian setting that more robustly accounts for uncertainty, yet there is no software with which a computationally intensive Bayesian approach to experimental design could be implemented...
December 1, 2016: BMC Evolutionary Biology
Selina C Wang, Dean J Tantillo
The results of density functional theory calculations on thiyl radical-promoted polycyclization to form dodecahedrane are described. On the basis of these results, the proposed polycyclization is predicted to be both highly exergonic and fast. These results showcase the potential power of radical polycyclization reactions in constructing complex molecular architectures.
December 1, 2016: Organic & Biomolecular Chemistry
Adrien Kaladji, Anne Daoudal, Aurélien Duménil, Cemil Göksu, Alain Cardon, Elodie Clochard, Antoine Lucas, Florent Lalys
BACKGROUND: The risk of long-term complications after endovascular aneurysm repair (EVAR) is still higher than open surgery and is a critical issue. This study aims to make available reliable statistical predictive models of complications after EVAR. METHODS: Two hundred and thirteen patients who underwent EVAR between 2002 and 2012 were included in this study. The preoperative CT-scans were analyzed with a dedicated workstation to provide spatially correct 3-dimensional data...
November 26, 2016: Annals of Vascular Surgery
M Radeski, V Ilieski
Temporo-spatial observation of the leg could provide important information about the general condition of an animal, especially for those such as sheep and other free-ranging farm animals that can be difficult to access. Tri-axial accelerometers are capable of collecting vast amounts of data for locomotion and posture observations; however, interpretation and optimization of these data records remain a challenge. The aim of the present study was to introduce an optimized method for gait (walking, trotting and galloping) and posture (standing and lying) discrimination, using the acceleration values recorded by a tri-axial accelerometer mounted on the hind leg of sheep...
December 1, 2016: Animal: An International Journal of Animal Bioscience
Yongming Zhao, Yurun Sun, Yang He, Shuzhen Yu, Jianrong Dong
A six-volt vertically-stacked, high current GaAs photovoltaic power converter (PPC) has been designed and fabricated to produce output power over 1 W under monochromatic illumination. An N(++)-GaAs/P(++)-AlGaAs tunnel junctions (TJs) structure has been used for connecting each sub-cell in this vertically-stacked PPC device. The thickness of the each GaAs sub-cell has been derived based on the calculation of absorption depth of photons with a wavelength of 808 nm using absorption coefficient obtained from ellipsometry measurements...
November 30, 2016: Scientific Reports
Rui-Rong Wang, Xiao-Qing Yu, Shu-Wang Zheng, Yang Ye
Location based services (LBS) provided by wireless sensor networks have garnered a great deal of attention from researchers and developers in recent years. Chirp spread spectrum (CSS) signaling formatting with time difference of arrival (TDOA) ranging technology is an effective LBS technique in regards to positioning accuracy, cost, and power consumption. The design and implementation of the location engine and location management based on TDOA location algorithms were the focus of this study; as the core of the system, the location engine was designed as a series of location algorithms and smoothing algorithms...
2016: SpringerPlus
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